tbuckley/cabot-search huggingface dataset:
Abstract 3014: PHGDH- A therapeutic vulnerability in melanoma
Authors: Neel N. Jasani, Florian Karreth
Journal: Cancer Research (2022)

Abstract Recurrently amplified oncogenes may represent melanoma vulnerabilities that can be exploited for therapy. The genomic locus containing the Phosphoglycerate Dehydrogenase (PHGDH) gene at chromosome 1p12 is frequently amplified in melanoma. PHGDH is the rate limiting enzyme that converts the glycolytic intermediate 3-Phospho Glycerate (3-PG) to serine through the serine synthesis pathway (SSP). Serine is utilized to make glycine, glutathione, one carbon metabolites, proteins and lipids. PHGDH inhibition suppresses proliferation of 1p12 amplified melanoma cells. However, the role of PHGDH in chromosome 1p12 non-amplified melanoma is poorly understood. We observed that 1p12 non-amplified melanoma cell lines have enhanced expression of the SSP enzymes as compared to melanocytes cultured in tetradecanoyl-phorbol acetate (TPA, a growth factor that stimulates MAPK pathway). Moreover, TPA starvation in melanocytes increased PHGDH expression. This led us to hypothesize that activation of oncogenic MAPK signaling leads to high expression of PHGDH which can serve as therapeutic vulnerability in melanomagenesis. Acute expression of oncogenic BRAFV600E in melanocytes resulted in upregulation of SSP enzymes, while treatment of melanoma cells with either BRAF or MEK inhibitor resulted in downregulation of SSP enzymes. We confirmed that PHGDH is regulated by BRAF-ERK-mTOR axis. Downregulation of PHGDH in 1p12 non-amplified melanoma cell lines decreased their cell proliferation and colony formation ability in vitro. We also observed that Phgdh knockdown in a BrafV600E/WT and Pten-/- (BPP) melanoma mouse model significantly increased survival. Furthermore, serine-glycine starvation (external source of Serine-glycine) in BPP chimeras did not affect the survival of these mice while on the other end, it suppressed the growth of the xenograft tumors injected in the NSG mice, which warrants further investigation. These results suggest the importance of PHGDH for melanoma cell proliferation and tumor growth irrespective of its amplification status. The exact mechanism of PHGDH regulation by BRAFV600E and the therapeutic effect of PHGDH inhibition in melanoma initiation and progression are the focus of our studies. Citation Format: Neel N. Jasani, Florian Karreth. PHGDH- A therapeutic vulnerability in melanoma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3014.
Abstract 6253: RNA-seq based somatic variant calling and gene expression analysis reveals tumor heterogeneity and metastatic potential in colorectal cancers
Authors: Ji Won Choi, Kwangsung Ahn, Sangsoo Kim, Dong-Il Park, Soo-kyung Park
Journal: Cancer Research (2022)

Abstract Colorectal cancer (CRC) is the third common malignant tumor and the second most responsible for worldwide cancer deaths. Also, RNAseq technology has been used for two purposes: to find exonic regions on the genome and quantify the expression level of the gene. We tried to validate the pipeline for identifying somatic variants from RNA-seq data, mainly following GATK4 somatic calling pipelines with some optimizing modifications. It is intended to examine whether somatic mutations driven from RNAseq data are associated with the biological behaviors of the individual colorectal cancer cells. We found that key genes (i.e., tumor suppressor genes such as APC and p53) are mostly mutated by T to C (in the non-coding region) or C to T (in the coding region) transitions, so that causes missense and nonsense mutations. However, highly mutated genes did not show significant expressional changes compared to the normal tissue. Otherwise, genes related to the metastatic potentials were observed to have highly increased expression. Our results can substantially verify the reliability of the somatic mutation calling approach using RNAseq data to call cancer-driving mutation and confirm an increase of extracellular matrix metabolism in the CRC. Citation Format: Ji Won Choi, Kwangsung Ahn, Sangsoo Kim, Dong-Il Park, Soo-kyung Park. RNA-seq based somatic variant calling and gene expression analysis reveals tumor heterogeneity and metastatic potential in colorectal cancers [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6253.
Abstract 2893: Exploring the combinatorial potential of bispecific T-cell engagers in high throughput format
Authors: Carla N. Castro, Daniel Feger, Sarah Ulrich, Oliver Siedentopf, Jan E. Ehlert
Journal: Cancer Research (2022)

Abstract Bispecific antibodies are being explored as a means to modulate responses of the immune system to tumor infiltration. They are emerging as a growing class of immunotherapies with potential to further improve clinical efficacy and safety. Besides tumor-targeted and dual immunomodulators, the most important class of therapeutically relevant bispecific antibodies are engagers of cytotoxic immune cells to kill tumor cells. These are mainly engager of T-cells (BiTE´s), but also NK-cell engager several of which have entered clinics with Blinatumomab (anti-CD3/anti-CD19) being FDA-approved for the treatment of Acute Lymphoblastic Leukemia. Several studies are under way to address potential combinatorial effects with other compounds in clinics. In order to facilitate analysis of the cytotoxic impact of BiTE´s in high throughput, we developed a 384-well format assay system based on Luciferase-labeled tumor cells. This detection technology has many advantages. As only the tumor cells are labeled, the specific detection of luciferase exclusively correlates to the number of viable tumor cells, allowing for co-cultures with high excess of effector cells without them interfering in the detection. Due to high sensitivity, only few tumor cells are required for a decent signal/noise ratio, keeping the overall need for primary effector cells to the lowest, even at high effector/target cell ratios. That can be of great advantage when working with rare cytotoxic subpopulations (e.g. NK-cells), precious samples from patients, or simply saves resources when performing large exploratory studies. In addition, combination of low 384-well format volumes with nanodrop agent dispensing technology minimizes amounts of expensive antibodies and other agents. Applying this technology, we evaluated the combinatorial effects of Blinatumomab with immune modulators (e.g. Lenalidomide), kinase inhibitors (e.g. MEK-inhibitor, Selumetinib) and other clinically relevant agents (e.g. MCL1-inhibitor, S63845) on the Luciferase-labeled GCB-like DLBCL cell line OCI-LY1. Depending on compound combination, we observe synergistic but also antagonistic effects. Our data support the outstanding usefulness of this methodological approach for the exploration of bispecific cytotoxic immune cell engager agents. Citation Format: Carla N. Castro, Daniel Feger, Sarah Ulrich, Oliver Siedentopf, Jan E. Ehlert. Exploring the combinatorial potential of bispecific T-cell engagers in high throughput format [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2893.
Abstract 3422: Combined treatment with interleukin-4 receptor-targeted cytotoxic peptide and PD-L1-blocking peptide efficiently induces immunogenic cell death of tumor cells and activates T-cell activity
Authors: Nawon Park, Byungheon Lee, Hyunsu Lee
Journal: Cancer Research (2022)

Abstract Immune checkpoint blockade therapy has provided clinical benefit to some patients with advanced cancer including melanoma and non-small cell lung cancer. However, many patients still fail to respond to single immune checkpoint blockade therapy. The need for combination therapies to increase anti-tumor responses is becoming important. Interleukin-4 receptor (IL4R) is frequently overexpressed in various cancer types and promotes tumor cell survival. PD-L1, a well-known immune checkpoint, is up-regulated in malignant tumors and inhibits T-cell activity. In this study, we aimed at a combination therapy using an IL4R-targeted cytotoxic peptide and PD-L1-blocking peptide. To target IL4R-high tumor cells, we exploited IL4RPep-1-KLA composed of IL4RPep-1, an IL4R-binding peptide, and (KLAKLAK)2, a cytotoxic peptide. IL4RPep-1-KLA induced necrosis as well as apoptosis of IL4R-expressing tumor cells and increased the secretion of CRT, HMGB1, and ATP, well-known markers of immunogenic cell death (ICD). Flow cytometry analysis showed that the conditioned medium of tumor cells treated with IL4RPep-1-KLA enhanced the expression of CD86 and CD80 on dendritic cells, suggesting the activation and maturation of dendritic cells through ICD. Sequential treatment with IL4RPep-1-KLA followed by PD-L1Pep-2, a PD-L1-blocking peptide, during the co-culture of tumor cells and CD8+ T-cells activated T-cell activity including T-cell proliferation and cytokine secretion more efficiently than single treatment with IL4RPep-1-KLA or PD-L1Pep-2, or simultaneous treatment. These results suggest that sequential, combined treatment with the IL4R-targeted cytotoxic peptide and PD-L1-blocking peptide can induce ICD of tumor cells and maturation of dendritic cells and subsequently activate T-cells. This treatment is a promising strategy for cancer immunotherapy. Citation Format: Nawon Park, Byungheon Lee, Hyunsu Lee. Combined treatment with interleukin-4 receptor-targeted cytotoxic peptide and PD-L1-blocking peptide efficiently induces immunogenic cell death of tumor cells and activates T-cell activity [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 3422.
Abstract 6262: Emergence of tumor mismatch repair deficiency and increased mutational burden in blood and tissue of metastatic colorectal cancer patients treated with temozolomide
Authors: Giovanni Crisafulli, Andrea Sartore-Bianchi, Luca Lazzari, Filippo Pietrantonio, Alessio Amatu, Marco Macagno, Ludovic Barault, Andrea Cassingena, Alice Bartolini, Paolo Luraghi, Gianluca Mauri, Paolo Battuello, Nicola Personemi, Valeria Pessei, Pietro Paolo Vitiello, Federica Tosi, Laura Idotta, Emanuele Valtorta, Emanuela Bonoldi, Giovanni Germano, Federica Di Nicolantonio, Silvia Marsoni, Salvatore Siena, Alberto Bardelli
Journal: Cancer Research (2022)

Abstract The majority of metastatic colorectal cancers (mCRC) are mismatch repair (MMR) proficient (MMRp) and unresponsive to immunotherapy, while MMR deficient (MMRd) tumors often respond to immune checkpoint blockade (ICB). We previously reported that treatment of CRC preclinical models with temozolomide (TMZ) leads to MMR deficiency, increased tumor mutational burden (TMB) and, sensitization to immunotherapy. To clinically translate these findings, we designed the ARETHUSA clinical trial whereby O6-Methylguanine-DNA-methyltransferase (MGMT) deficient, MMR proficient and KRAS mutant mCRC patients receive priming therapy with TMZ. Analysis of solid tissue biopsies and circulating tumor DNA (ctDNA) obtained after TMZ treatment revealed the emergence of TMZ mutational signature, alterations in MMR genes and increased TMB in 14 out of 16 patients. Genetic mutations induced by TMZ were dose-dependent and multiple alterations in the nucleotide context favored by the TMZ signature emerged in MMR genes such as the MSH6 T1219I variant which was detected in ctDNA and tissue of 13/14 (93%) of the cases. A subset of the patients whose tumors after TMZ priming displayed the MSH6 mutation, the TMZ mutational signature and increased TMB, achieved disease stabilization upon pembrolizumab treatment. Overall, we provide proof-of-concept that treatment of MGMT deficient/MMR proficient KRAS mutant mCRCs with TMZ can be tracked by mutational signature analysis and lead to inactivation of the MMR pathway, emergence of the TMZ mutational signature, TMB increase, and, in some cases, to disease stabilization during ICB. Citation Format: Giovanni Crisafulli, Andrea Sartore-Bianchi, Luca Lazzari, Filippo Pietrantonio, Alessio Amatu, Marco Macagno, Ludovic Barault, Andrea Cassingena, Alice Bartolini, Paolo Luraghi, Gianluca Mauri, Paolo Battuello, Nicola Personemi, Valeria Pessei, Pietro Paolo Vitiello, Federica Tosi, Laura Idotta, Emanuele Valtorta, Emanuela Bonoldi, Giovanni Germano, Federica Di Nicolantonio, Silvia Marsoni, Salvatore Siena, Alberto Bardelli. Emergence of tumor mismatch repair deficiency and increased mutational burden in blood and tissue of metastatic colorectal cancer patients treated with temozolomide [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 6262.
Abstract 5563: Development of an integrated <i>in vitro</i> and <i>in vivo</i> OVA-specific system for cancer vaccine discovery
Authors: Jian Xiang, Jun Huang, Wenrong Zhou, Zhengang Peng, Qingyang Gu, Qunsheng Ji
Journal: Cancer Research (2022)

Abstract As the development of cancer immunotherapy and urgent demand of precision medicine, cancer vaccines have been envisioned as a novel and effective tool to cure cancer disease or prevent cancer from recurrence or metastasis. In order to support the research and development of new modality in drug discovery, we have established an advanced and integrated in vitro and in vivo platform for various types of cancer vaccine, such as peptide vaccine, mRNA vaccine, DC vaccine and so on. Ovalbimin (OVA) is a key model antigen which has been widely used in vaccination experiments. Here we established an OVA overexpressed system based on different types of tumor cells, such as B16F10-OVA and MC38-OVA. Firstly, we proved that MHC-I:OVA complex were presented on the surface of stable cell lines successfully through IFN stimulation. The results of in vitro CD8+ T cells killing assay showed the B16F10-OVA cells can be largely killed which indicates OVA protein has been presented and can be utilized as a specific target for analysis. In vitro ELISPOT assay is well characterized for efficiency tool for immunogenicity determination. Using ELISPOT assay, we compared the immunogenicity of OVA specific peptide and mRNA administration via different injection manners. Furthermore, in vivo tumor model of B16F10-OVA and MC38-OVA have also been established to evaluate the anti-tumor efficacy of peptide and mRNA vaccine. The mechanism of cancer vaccine has also been investigated via T cell, B cell and other cell populations blocking. Additionally, we explored the target protein biodistribution and in vivo behavior of mRNA vaccine carrier with Lumina LT system. In summary, the integrated OVA-specific system can be used for new adjuvants and peptide/mRNA carrier exploration in cancer vaccine discovery. Citation Format: Jian Xiang, Jun Huang, Wenrong Zhou, Zhengang Peng, Qingyang Gu, Qunsheng Ji. Development of an integrated in vitro and in vivo OVA-specific system for cancer vaccine discovery [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 5563.
Abstract 556: Novel anti-TACI single and dual-targeting CAR T cells overcome BCMA antigen loss in multiple myeloma
Authors: Rebecca C. Larson, Ana Castano, Amanda A. Bouffard, Michael C. Kann, Andrea Schmidts, Kathleen M. Gallagher, Marcela V. Maus
Journal: Cancer Research (2022)

Abstract Anti-BCMA CAR T cell therapy has had success clinically against multiple myeloma, recently leading to FDA approval. However, the median progression free survival is 8.8 months, suggesting that targeting BCMA alone may not be sufficient. Reports of BCMA-negative relapse have occurred, highlighting the need for therapeutics that can overcome antigen loss. We have generated a novel antibody against a second target in multiple myeloma, transmembrane activator and CAML interactor (TACI). This antibody specifically recognizes TACI-positive cells (with either endogenous or exogenous expression) and has no recognition of non-B cell peripheral blood mononuclear cells. We designed novel second-generation CAR T cells based on the single chain variable fragment (scFv) from this antibody. We observe that anti-TACI CARs are cytotoxic in vitro at comparable levels to anti-BCMA CAR against multiple myeloma cell lines MM1S and RPMI-8226. Anti-TACI CARs are also functional in vivo and expand in peripheral blood of xenograft multiple myeloma models. We generated BCMA-knockout MM1S cells and observe that while anti-BCMA CAR treated mice have outgrowth of tumor, anti-TACI CAR treated animals retain anti-tumor activity. To overcome potential antigen loss of either BCMA or TACI, we designed tandem bispecific CAR T cells based on both single-targeting CAR designs. These BCMA and TACI dual-targeting CARs are functional in vitro and in vivo, even in the context of single antigen loss. We monitor the activation (CD69), exhaustion (PD-1, TIM-3, LAG-3), and memory (CCR7, CD45RA) phenotype over time to investigate the differences of single versus dual-targeting CAR T cells. We also study the ability of these CAR T cells to bind soluble antigen, as well as their binding avidity to tumor cells. We observe that the anti-TACI scFv more proximal to the CD3ζ signaling domain has a stronger effect on CAR functionality than when this scFv is more distal. Our studies provide a potential superior therapeutic option which remains efficacious in the context of BCMA antigen loss. Citation Format: Rebecca C. Larson, Ana Castano, Amanda A. Bouffard, Michael C. Kann, Andrea Schmidts, Kathleen M. Gallagher, Marcela V. Maus. Novel anti-TACI single and dual-targeting CAR T cells overcome BCMA antigen loss in multiple myeloma [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 556.
Abstract 2688: Bombesin receptors regulate transactivation of HER4
Authors: Terry W. Moody, Irene Ramos-Alvarez, Samuel A. Mantey, Robert T. Jensen
Journal: Cancer Research (2022)

Abstract Bombesin (BB) is an autocrine growth factor for non-small cell lung cancer (NSCLC) cells. BB stimulates whereas the BB2 receptor (R) antagonist PD176252 inhibits NSCLC growth (Moody et al., Eur. J. Pharmacol; 2003; 474:21). The BB2R regulates the transactivation of the EGFR, HER2 and HER3 (Lee et al., BBAMCR 2020; 1867: 118625). HER4 increases the proliferation of NSCLC cells (Mota et al., Oncotarget 2017; 8: 89284). It is unknown if BB2R stimulation increases tyrosine phosphorylation of HER4 and this was investigated using NSCLC cells. BB or neuregulin (NRG1) addition to NSCLC cells increased the phosphorylation of Tyr1284-HER4. By RT-PCR and western blot, mRNA and protein for BB2R, HER4 and NRG1 was present in NCI-H522 and NCI-H661 NSCLC cells. The addition of BB to NCI-H522 or NCI-H661 cells increased phosphorylation of HER4, ERK and AKT which was blocked by PD176252. By immunoprecipitation, HER4 heterodimerized with HER2 and the EGFR after addition of BB to NSCLC cells. PP2 and N-acetylcysteine impaired the ability of BB to increase P-Tyr1284-HER4 in NSCLC cells, which indicates that SRC and reactive oxygen species are essential. Ibrutinib, a tyrosine kinase inhibitor (Rauf et al., Oncogene 2018; 37: 2237), impaired the ability of BB2Rs to regulate HER4 transactivation. Ibrutinib or PD176252 inhibited the growth of NSCLC cells whereas BB or NRG1 increased NSCLC colony formation. The results indicate that peptide receptors for BB regulate HER4 transactivation and the proliferation of NSCLC cells. Citation Format: Terry W. Moody, Irene Ramos-Alvarez, Samuel A. Mantey, Robert T. Jensen. Bombesin receptors regulate transactivation of HER4 [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr 2688.
Abstract LB175: MicroRNA-138 suppresses glioblastoma proliferation through downregulation of CD44 and sensitizes to temozolomide
Authors: Tae Jin Lee, Ji Young Yoo, Deokhwa Nam, Ji Seon Shim, Alberto Bueso-Perez, Balveen Kaur
Journal: Cancer Research (2022)

Abstract Tumor suppressive microRNAs (miRNAs) are increasingly implicated in the development of anti-tumor therapy by reprogramming gene network that are aberrantly regulated in cancer cells. This study aimed to pinpoint tumor suppressive miRNAs with therapeutic potential against GBM, one of the most deadly cancers. Whole transcriptome and miRNA expression profiling analyses were performed on human GBM patient tissues. Transient transfection of miRNA mimics was used to investigate the tumor suppressive role of a miRNA (miR-138) in cell proliferation, cell cycle, migration, would healing, and chemosensitivity to temozolomide (TMZ). Orthotopic xenograft mice model using human patient-derived primary GBM cells was used for the survival studies. miR-138 was found as one of the most significantly downregulated miRNAs with an inverse correlation with CD44 expression. Functional studies unveiled that miR-138 negatively regulates the expression of CD44 at protein level by directly binding to the 3’ UTR of CD44. CD44 inhibition by miR-138 overexpression resulted in an inhibition of glioblastoma cell proliferation in vitro through cell cycle arrest as evidenced by a significant induction of p27 and its translocation into nucleus. Ectopic expression of miR-138 also increased survival rates in mice that had an intracranial xenograft tumor derived from human patient-derived primary GBM cells. In addition, miR-138 sensitized GBM tumor to TMZ in mice. We demonstrated a therapeutic potential of tumor suppressive miR-138 through direct downregulation of CD44 and sensitization to chemotherapy for the treatment of primary and even chemoresistant GBM Citation Format: Tae Jin Lee, Ji Young Yoo, Deokhwa Nam, Ji Seon Shim, Alberto Bueso-Perez, Balveen Kaur. MicroRNA-138 suppresses glioblastoma proliferation through downregulation of CD44 and sensitizes to temozolomide [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2022; 2022 Apr 8-13. Philadelphia (PA): AACR; Cancer Res 2022;82(12_Suppl):Abstract nr LB175.